Ever since Telus forced us to put our 2 Telus domain email accounts onto Google/Gmail it's a big pain managing our Telus email. Google is constantly bugging us about multiple Gmail identities, logging us out of our accounts, etc. We both already had a gmail account before this and are not interested in amalgamating those accounts with the Telus email account. Google keep sending us messages about this on our computer and logging us out of our different Telus accounts/we have to log back in.
We've also had an issue with Google hiding important email from sources like our building management company in a spam folder where we don't see the messages. I just went through a long procedure trying to find ways to stop them doing that, and I'm trying setting up filters blocking this behaviour. I had already previously marked these messages as "not spam" but that didn't work. This didn't used to happen when we accessed webmail on the Telus domain directly.
As far as I'm concerned what Telus did by outsourcing customer email was unilaterally change/downgrade a service that they were contracted to give their internet customers, without consultation and without recourse.
Who is US and WE?
My wife and I both had our own Telus email accounts and now both have the new sperate Telus GMail accounts. There's no reason for 2 people to be 'amalgamating' their email accounts.
If you are using Chrome as your browser you may want to use multiple Chrome profiles to access your multiple email domains. I have two profiles, each with a separate icon on my desktop and have none of the problems you identified.